Trace the requested class
- Capture the failing workflow and ProgID/CLSID if source or tracing exposes it.
- Resolve registration in the 32-bit registry view used by VB6.
- Verify registered server path, architecture and interface/type-library version.
- For in-process servers inspect native dependencies; for out-of-process servers inspect launch and permissions.
- Compare with a working machine before changing registration.
Why regsvr32 may not solve it
The server may be an EXE, not self-registering, incompatible with the client or blocked by a missing dependency. Successful registration does not prove activation or interface compatibility.
Use COM troubleshooting for identity/interface analysis, registration errors when the command fails and DLL diagnosis for loader failures. See the VB6 pillar.
Provide error context, CLSID/ProgID, component files/versions and working-machine registration.